Light-weight portable fire extinguishers



July 5, 1966 P. M cRossAN 3,259,194

LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Filed April 20, 1964 2Sheets-Sheet 1 W w (g INVENTOR 'PA-TR m I: Mc Qeo s s 6! BY JK ATTOE'NEYS y 5, 1956 P. MGCROSSAN 3,259,194

LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Filed April 20, 1964 2Sheets-Sheet 3 2; A /M W A T TORNEYS United States Patent 3,259,194LIGHT-WEIGHT PORTABLE FIRE EXTINGUISHERS Patrick McCrossan, HaywardsHeath, Sussex, England, assignor to Stoppafire Limited, Manchester,England Filed Apr. 20, 1964, Ser. No. 360,995 8 Claims. (Cl. 169-31) Thepresent invention relates to fire extinguishers, and particularly,although not exclusively, to the portable kind known as water type (gaspressure) extinguishers. A general description of extinguishers of thiskind will be found in British Standards Institute specification No.1,382 (1948).

The invention is suitable also for use with other types of extinguishersuch as those using carbon tetrachloride, or soda-acid extinguishers andfoam extinguishers.

In water (gas pressure) extinguishers a high pressure gas cartridge isscrewed into the head of the container which is filled to a requiredlevel with Water. The extinguisher is operated by striking a knob. Thisbreaks or pierces the gas cartridge and the gas is released into theextinguisher which then discharges a jet of water to a distancegenerally of about 40 ft.

Due to the high internal pressure the container has to withstand(normally up to 500 psi), known containers have been constructed ofmetal, either copper or specially treated steel. The ancillary partssuch as the cap and hose fitment are also normally constructed of metal.This adds considerably to the weight of the extinguisher and alsointroduces the risk of corrosion.

According to the present invention there is provided a method of makinga container for a fire extinguisher comprising the steps of producing,by moulding a thermosetti-ng resin, two cups one of which is formed witha pair of apertures at or near its otherwise closed end, sealing intothe apertures a striker mechanism and a hose fitment respectively,loading the apertured cup with fire extinguishing accessory apparatussuch as a gas cartridge and sealing the cups together at their openends.

According to a further feature of the invention, there is provided afire-extinguisher container comprising two cups made of thermosettingresin sealed together at their open ends, one cup being formed with twospaced apertures at or near its otherwise closed end, a strikermechanism and a hose fitment being sealably fitted in the two aperturesrespectively.

The material used for the container must have a high tensile strength.It is therefore preferred not to use thermoplastic resins whichgenerally retain some thermal stress after moulding and are liable tosoften and lose shape at above average atmospheric temperatures. Manyknown types of thermosetting resin are now known which would be suitablewhen reinforced, as will be apparent to those skilled in the moulding ofplastics. Particularly suitable materials are the group known as DoughMoulding Compounds (D.M.C.) which comprise a base of polyester orepoxide resin in which is dispersed a high content of filler orreinforcement material, which in the preferred compounds includes glassfibre of various lengths.

Such compounds are suitably moulded by compression. A male tool isbrought down upon a female mould containing the D.M.C. (with theaddition if necessary of a catalyst or hardener) in suitable quantityand the viscous material is forced to fill the space in between andallowed to set.

An example of a suitable D.M.C. compound is the product sold under theregistered trade mark Rockite K-50l, which is a glass fibre rein-forcedpolyester resin. This has a specified tensile strength of 7,000-10,000p.s.i.

3,259,194 Patented July 5, 1966 ice It has also other propetries ofparticular advantage in the present invention, namely:

(1) Good impact strength over a wide temperature range.

(2) Flexural and tensile strengths which do not vary appreciably withtemperature.

(3) Ability to withstand exposure without too high a degree of ageing. Y

(4) Low water absonption.

(5) High thermal stability.

It will be appreciated however, that many other materials having similarproperties are now commercially available, in particular they are commonto nearly all compounds of the D.M.C. group. Preferred reinforcedsynthetic resin compounds should have a tensile strength of over 5,000p.s.i.

A preferred embodiment of the invention will now be described by way ofexample and with reference to the accompanying diagrammatic drawings, inwhich:

FIG. 1 is a longitudinal cross-section through a water gas pressure)fire extinguisher of the invention, including a hose connection, and

FIG. 2 is a view partly in cross-section of the combined hose andconnector and nozzle holder on a larger scale.

The illustrated fire extinguisher container 1 is moulded in two parts,each Otf cup-like shape, namely an upper cup 2, and a lower cup 3, bothbeing formed from Rockite K5 01. The cups are formed with male andfemale screw threads, respectively, at their open ends and the thicknessof the walls is suitably increased to take these threads. Preferably anindustrial adhesive is applied to the threads before the two cups arejoined so that a verystrong sealed joint is formed. The formation of thecontainer in two parts as illustrated in FIG. 1 makes the mouldingoperation much easier and also aids the fitting of the internalaccessory parts which are preferably fitted before the two cups arejoined. The completed container 1 has a slight barrel shape which addsto its strength and which also allows easy access to the interiors ofthe two cups 2 and 3 before they are joined.

The upper container cup 2 is moulded with an aperture in ascrew-threaded neck 4 to hold a screw cap 5. The screw cap 5 is alsoadvantageously moulded from synthetic resin material and D.M.C. ispreferred. The screw cap is formed with a bore 6 to hold a metal strikermechanism comprising a rod 7 which is fitted with a knob 8 of syntheticresin material. D.M.C. is again suitable, or nylon. The striker rod hasa pointed lower end and is adapted to pierce a gas cartridge (not shown)in conventional manner when the knob 8 is struck. The protruding part ofthe striker rod 7 and the knob 8 are covered when not in use by aprotective cap 9 which is suitably moulded from polyethylene of mediumdensity.

The upper container cup 2 is also formed with an apertured thickenedshoulder portion 10 to hold a mounting ring 11 for a hose fitmentindicated generally at 15. The mounting ring 11 is shown moulded intothe shoulder portion 10. It is itself preferably moulded from D.M.C. andmay be formed integrally with the upper container cup 2. Alternativelyit may take the form of an externally threaded tube retained upon thecontainer cup 2 by nuts and washers, the container cup 2 being mouldedwith a flat, thickened portion to provide an air tight seal.

A tube 12, preferably of polyethylene, extends inside the container fromthe mounting ring 11 to a point near the bottom of the container and isprovided at its lower end with a filter rose 13. The tube 12 is held inplace on the mounting ring 11 by means of an inner sleeve 14.

A hose stem 16 is joined to the mounting ring 11 from the outside. Thestem 16 has one end threaded both internally and externally. This end isscrewed on to a portion of the inner sleeve 14 which protrudes throughthe mounting ring 11, a washer 17 being provided to form a good seal. Aretaining nut 18 is threaded on the outside of the stem 16.

The other end of the hose fitting 15, i.e. the end remote from thecontainer 1, is formed with a union joint 19 (FIG. 2). The end of theunion joint containing the bore for the fire-extinguishing liquid isformed in suitable manner as illustrated to retain a low densitypolythene hose 20, a hose connector 21 being provided to hold the hose20 firmly in position. The other end of the hose is provided with anozzle 22 which for convenience is held in a socket 23 at the back ofthe union joint 19, so that it is protected from being clogged with dirtor damaged. The hose may conveniently be wound around the extinguisher.

The Whole of the hose fitting, including the stem 16, union joint 19 andhose connector 21, is preferably moulded from D.M.C. These parts are notrequired to be of such high tensile strength as the container, but theymust have a high impact strength so as to be resistant to wear and tearover extended periods. The hose nozzle 22 is preferably moulded inmedium density polyethylene. The container may have a capacity forconvenient use of about two gallons.

Portable fire extinguishers according to the invention, such as the oneillustrated, are very much lighter than metal extinguishers in currentuse, and consequently may be handled much more quickly. This addsgreatly to their fire-fighting efificiency, and enables small models tobe used by people of slight strength such as school children.

What we claim is:

1. A container for a portable fire extinguisher comprising tWo cupsmoulded from thermosetting resin, one of which cups is formed with apair of apertures at its otherwise closed end, a striker mechanismsealed into one of said apertures and a hose fitting sealed into theother of said apertures, said fitting including a combined hoseconnector and nozzle retaining socket, and means sealing the cupstogether releasably at their open ends.

2. A container for a portable fire extinguisher comprising two cups madeof thermosetting resin reinforced with glass fibers and removably sealedtogether at their open ends, one cup being formed with two spacedapertures at its otherwise closed end, a striker mechanism and a stemfitting being sealably fitted into the two apertures respectively, saidstern fitting terminating in a joint unit.

carrying a hose connector and a nozzle holding socket, a hose having acoupling at one end, a nozzle at the other end and means securing saidcoupling end of the hose to the connector and said nozzle andtemporarily in said nozzle holding socket.

3. A container for a portable fire extinguisher adapted to receive ahigh pressure gas cartridge and wherein the container must withstandhigh internal pressure up to approximately 500 p.s.i. comprising twomolded cups each formed of reinforced thermosetting resin of hightensile strength, said two cups being interconnected with one another bymale and female threads formed on the respective cups at the open endsthereof, said two cups when in assembled relationship defining agenerally barrel-shaped outer configuration for the container with itsmaximum dimension at an intermediate portion of the container adjacentsaid threaded ends of the cups, one of said cups having a generallydome-shaped closed end and defining a strengthened bottom for thecontainer, the other of said cups including a heavy shoulder portionspaced a substantial distance from the threads formed thereon, saidshoulder portion joining with a relatively narrow neck having an openend, a cap closing off the open end of said neck, a striker mechanismmovably supported by said cap and being adapted to reach a vulnerablepart of a high pressure gas cartridge supported by the container, saidshoulder having a recess formed therein, a mounting ring snugly disposedwithin said recess and sealed with respect to said container, said ringhaving a bore formed therethrough, and a tubular member extendingthrough the bore in said mounting ring and sealed with respect theretofor discharging liquid from the interior of said container outwardly ofsaid tubular member.

4. Apparatus as defined in claim 3 including a rupturable adhesivebetween the male and female threads formed on the respective cups.

5. Apparatus as defined in claim 3 wherein said striker mechanismcomprises a rod slidably supported by said cap.

6. Apparatus as defined in claim 3 wherein said thermosetting resinconsists of a polyester resin.

7. Apparatus as defined in claim 3 wherein said thermosetting resinconsists of an epoxide resin.

8. Apparatus as defined in claim 3 wherein said resin is reinforced withglass fibers.

References Cited by the Examiner UNITED STATES PATENTS 2,105,487 1/1938Lozon.

2,204,015 6/1940 Iftiger et al.

2,426,024 8/1947 Jones et al. 16931 2,571,877 10/1951 HenshaW 169-31EVERETT W. KIRBY, Primary Examiner.

J. HUSSER, Assistant Examiner.

3. A CONTAINER FOR A PORTABLE FIRE EXTINGUISHER ADAPTED TO RECEIVE AHIGH PRESSURE GAS CARTRIDGE AND WHERIN THE CONTAINER MUST WITHSTAND HIGHINTERNAL PRESSURE UP TO APPROXIMATELY 500 P.S.I. COMPRISING TWO MOLDEDCUPS EACH FORMED OF REINFORCED THEREMOSETTING RESIN OF HIGH TENSILESTRENGTH, SAID TWO CUPS BEING INTERCONNECTED WITH ONE ANOTHER BY MALEAND FEMALE THREADS FORMED ON THE RESPECTIVE CUPS AT THE OPEN ENDSTHEROF, SAID TWO CUPS WHEN IN ASSEMBLED RELATIONSHIP DEFINING AGENERALLY BARREL-SHAPED OUTER CONFIGURATION FOR THE CONTAINER WITH ITSMAXIMUM DIMENSION AT AN INTERMEDIATE PORTION OF THE CONTAINER ADJACENTSAID THREADED ENDS OF THE CUPS, ONE OF SAID CUPS HAVING A GENERALLYDOME-SHAPED CLOSED END AND DEFINING A STRENGTHENED BOTTOM FOR THECONTAINER, THE OTHER OF SAID CUPS INCLUDING A HEAVY SHOULDER PORTIONSPACED A SUBSTANTIAL DISTANCE FROM THE THREADS FORMED THEREON, SAIDSHOULDER PORTION JOINING WITH A RELATIVELY NARROW NECK HAVING AN OPENEND, A CAP CLOSING OFF THE OPEN END OF SAID NECK, A STRIKER MECHANISMMOVABLY SUPPORTED BY SAID CAP AND BEING ADAPTED TO REACH A VULNERABLEPART OF A HIGH PRESSURE GAS CARTRIDGE SUPPORTED BY THE CONTAINER, SAIDSHOULDER HAVING A RECESS FORMED THEREIN, A MOUNTING RING SNUGLY DISPOSEDWITHIN SAID RECESS AND SEALED WITH RESPECT TO SAID CONTAINER, SAID RINGHAVING A BORE FORMED THERETHROUGH, AND A TUBULAR MEMBER EXTENDINGTHROUGH THE BORE IN SAID MOUNTING RING AND SEALED WITH RESPECT THERETOFOR DISCHARGING LIQUID FROM THE INTERIOR OF SAID CONTAINER OUTWARDLY OFSAID TUBULAR MEMBER.